Square root of 512k^2. show work

We are asked to evaluate the square root of the expression  512 k^2.512 is not a perfect square but is divisible by the perfect square 256. square root of 256 is 16. hence square root of 512 is 16 square root of 2. square root of k2 meanwhile is equal to k. The answer hence is  16k square root of 2

(1/x + 1)^2 + 6 (1/x + 1) +5